in my experience with the Rosenthal Arlington/Ballston dealer's service dept, they are decent enough to deal with. Just make sure you tell them exactly what needs done and do not get talked into doing extra things that aren't necessary, and they shouldn't give you (or your sister) too much trouble.
my experience with dealers is, don't mix the sales dept with the service dept, they ususally operate independently of each other, the behavior of one do not necessarily reflect the behavior of the other.
talk to Brian Lawless at Rosenthal Arlington's service dept, he was up front and thorough with me when I dealt with him to have my RX-7 worked on.